1. Field of the Invention
The present invention relates to a method for alignment processing of alternately forming two kinds of slit alignment regions in different aligned states while moving a substrate and relates specifically to a method and an apparatus for alignment processing that can reduce takt time of the alignment processing.
2. Description of Related Art
In this type of conventional method for alignment processing, a photo mask in which slit openings are formed at a fixed array pitch is used, and first ultraviolet irradiation is applied to a substrate coated with an aligned film from an oblique direction. After that, the substrate or both the substrate and the photo mask are rotated 180 degrees to shift a relative position of the photo mask to the substrate, and, thus, to apply second ultraviolet irradiation to a region not subjected to the first ultraviolet irradiation (for example, see Japanese Patent No. 4201862).
In another method for alignment processing, a photo mask in which slit openings are formed at a fixed array pitch is used, and ultraviolet light is irradiated to an aligned film on a substrate from a 45° direction with respect to the perpendicular of the substrate through the openings of the photo mask. The photo mask is then shifted, and polarized ultraviolet light is irradiated from a 45° opposite direction with respect to the perpendicular of the substrate (for example, see Japanese Laid-open (Kokai) Patent Application Publication No. 2002-31804).
In yet another method for alignment processing, while a color filter substrate is moved along its surface direction, ultraviolet light is irradiated to the color filter substrate coated with an aligned film from an oblique direction through a photo mask in which a plurality of openings are formed at a fixed array pitch in a direction perpendicular to the moving direction of the color filter substrate, and half of the region of each picture element of the color filter substrate is exposed. After that, the exposure position is shifted by a half pitch, and the irradiation angle of ultraviolet light is changed to expose a remaining half of the region of each picture element (for example, see Japanese Laid-open (Kokai) Patent Application Publication No. 2007-41175).
However, in any of the above conventional methods for alignment processing, since two kinds of alignment regions in different aligned states are formed through two times of alignment processing, the takt time of the alignment processing cannot be reduced.
In the method for alignment processing disclosed in Patent Literature 1, after the first ultraviolet irradiation, the substrate is rotated 180 degrees to apply the second ultraviolet irradiation to the region not subjected to the first ultraviolet irradiation. Therefore, two different photo masks, that is, the photo mask for the first ultraviolet irradiation and the photo mask for the second ultraviolet irradiation are required to be used, and there is a problem that the cost of the photo mask is increased.
In the method for alignment processing disclosed in Patent Literatures 1 and 2, since the alignment processing is batch processing, it is difficult to increase the number of substrates subjected to the alignment processing per unit of time.
In the method for alignment processing disclosed in Patent Literature 3, although the alignment processing can be performed while the substrates are continuously supplied, two apparatuses for alignment processing are required to be provided to be arranged in the moving direction of the substrate, and there is a problem that the cost of the device is increased.